Between the Poles

New ASCE standard guideline for recording and exchanging utility infrastructure data is imminent

The release of the new ASCE Standard Guideline for Recording and Exchanging Utility Infrastructure Data (also referred to as the utility as-built standard) developed under the auspices of the American Society of Civil Engineers (ASCE’s) Construction Institute(CI) and Utility Engineering and Surveying Institute (UESI) is imminent. The standard draft passed committee ballot in November 2019 and in January 2020 all comments were addressed. Next step is a reconciliation report and then the standard will be available for public comment. The Open Geospatial Consortium (OGC) has already adopted the standard draft for the Model for Underground Data Definition and Integration (MUDDI) initiative.

The purpose is to facilitate data collection, data management, and data exchange among stakeholders. It is designed to complement the widely used ASCE 38-2 Standard Guidelines for the Collection and Depiction of Existing Subsurface Utility Data. 

As a reminder ASCE 38-02, published in 2002, is intended to standardize the classification of the quality of location information about existing subsurface utility networks on engineering drawings. The standard defines four quality levels based on method used to determine the location of underground assets. 

1. Precise horizontal and vertical location of utilities obtained by the actual exposure and subsequent measurement of subsurface utilities, usually at a specific point.  Accuracy is typically set to 15-mm vertical and to applicable horizontal survey and mapping accuracy as defined or expected by the project owner.
   
2. Information obtained through the application of appropriate surface geophysical methods to determine the existence and approximate horizontal position of subsurface utilities.
3. Information obtained by surveying and plotting visible above-ground utility features and by using professional judgment in correlating this information to Quality Level D.
4. Information derived from existing records or oral recollections.

The basic deliverable for utility information is a CAD file or plan sheet that has quality levels A, B, C, and D and assigned to each asset.  Quality level A data typically requires a supplemental data form with additional information. This standard does not address the quality of vertical information other than for quality level A data.

New ASCE Standard Guideline for Recording and Exchanging Utility Infrastructure Data

A white paper on the new ASCE standard was published in 2018 which provided an overview of the new standard and its intended use cases. (The actual standard when it is made available publicly may differ from the white paper.)The new guidelines are targeted on two use cases;

1. capturing and recording the location of new utility data at the time it is installed and for
2. recording location data for existing utilities exposed during construction.

It is intended as non-binding guidance to assist right-of-way and utility owners in establishing their own standards.  The objective of the guideline is to provide a common definition for communicating the positional accuracy of utility assets and define a minimum set of data attributes necessary to communicate the position along with the type of equipment, geometry, function, ownership, materials, status and other information for each asset. The guideline specifies essential elements for documenting the location and attributes of underground and above-ground utility infrastructure, especially for newly installed utilities and for utilities exposed during construction. It defines levels of positional accuracy of utility infrastructure.

Positional accuracy

ASCE 38-02 is not prescriptive with respect to accuracy and is generally 2D in focus, whereas more modern quality standards such as PAS 128, the French DICT, and Canadian CSA S-250 which reflect modern technical developments specify accuracy in 3D. The new standard guidelines specify positional accuracy. 

Data model

The guideline does not provide a prescriptive utility data model but defines the elements of utility data needed to facilitate exchange of a 3D utility model with sufficient attributes for civil engineering.

The guidelines also require that metadata should be provided with all exchanged data including feature type, how and when the data was collected, the coordinate reference system and datum used, the individual(s) who certified the data, and any known limitations.

By the way March 16th is the deadline for public consultation and comments on the PAS128 2020 Revision.

Elements for improving underground utility mapping to reduce risk of damage during construction

Without accurate maps of underground infrastructure, every construction project has the potential to become a disaster site. Unlike the aviation industry where reliable data is collected and is accessible to investigators to prevent disasters from happening in the future, there is limited access to data about the location of underground infrastructure and what data is accessible is inaccurate, out-of-date and incomplete with the result that serious incidents during construction with injuries and fatalities occur again and again.  It is estimated that in the United States $10 billion is devoted to locating underground infrastructure prior to and during construction, but the available statistics indicate that this is not reducing the number or severity of incidents of underground utility damage.  Furthermore inaccurate and missing information about underground infrastructure increases the risk of schedule and budget overruns.  It has been estimated that this represents a $50 billion drag on the U.S. economy and upto a £6 billion drag on the U.K. economy.

Nearly every month the news carries reports of explosions caused by damage to underground utilities during construction excavation. In the last few months of this year there have been explosions in Murrieta, California (July) where a utility worker was killed and 15 others injured, downtown San Francisco (February), Durham, North Carolina (May), and I could go on. These incidents are more frequent than many people realize. 

This is not an impossible problem. A number of cities, regions and countries around the world have recognized the importance of accurate information about the location of underground infrastructure and implemented processes to reduce the risk of these events. For example, comparing the United States and Japan reveals a startling difference in the number of incidents of underground utility damage during construction. The number of incidents in the U.S. is between 400,000 and 800,000 per year (roughly one or two every minute). For all of Japan the number of incidents in 2016 was 134. Clearly something can be done to reduce the risk for construction workers and the public.

Over the years I have personally compiled information on 25 jurisdictions including airports in the Americas, Europe, and Asia Pacific that have implemented various policies and organizational structures for sharing information about the location of underground infrastructure. These range from government mandated and implemented, government mandated and privately implemented, voluntary industry associations, and private companies. In this article I provide a synthesis of measures most of which have been implemented, are being implemented, or have undergone pilot implementations. These can be grouped in several broad categories.

• Reliable statistics on underground utility damage

• Policies, procedures, and technologies for raising the level of accuracy, timeliness and completeness of information about the location of underground infrastructure.

• Digitalizing the capture, sharing and updating of location information about underground infrastructure.

• Ensuring security and privacy of location information about underground networks including protection for competitive information. 

• Providing access to stakeholders to underground infrastructure location information throughout the construction project life-cycle from planning and design through construction to operations and maintenance.

• Liability model for sharing responsibility for costs of underground utility damage.

Airports, university campuses, and industrial campuses are characterized by a greater density of underground utilities and by more types of underground equipment( communications cables, aeronautical ground lighting cables, gas mains, low voltage electric power cables, high voltage electric power cables, storm water mains, sanitary waste water mains, potable water mains, grey water mains, fuel mains, fire fighting water mains, and a variety of underground structures.) Underground infrastructure in airports, university and industrial campuses typically has a single owner though not always.

Public jurisdictions such as national, regional, state or provincial and municipal governments are responsible for the public right of way.  Typically underground infrastructure in the public right of way involves multiple private owners; telecom network operators, electric power utilities, gas network operators, water and wastewater operators,and others such as heating and fuel transmission pipeline operators. Dealing with multiple private owners who attempt to maintain information about their network facilities typically in a GIS considerably complicates the process of acquiring and maintaining accurate location information about underground cables and pipes.

1. Reliable statistics are essential to determine the social impact of underground utility damage and to assess the effectiveness of policies, procedures and technologies designed to reduce the number and severity of incidents of underground utility damage. Every incident of damage to underground infrastructure should be reported including injuries, fatalities and direct cost. Indirect cost is a nice to have, but very difficult to estimate. Cause is difficult to determine because it depends on who is reporting the incident - network operator, the excavator, or by an independent organization.  A network operator's perspective may be that the contractor did not exercise care during excavation, whereas the contractor's perspective may be that the location of the cable or pipe as identified as a result of a one-call request was inaccurate.  Responsibility for submitting this information has to be assigned to the   One option for doing this efficiently is to classify incidents by seriousness and assign different levels of reporting based on this classification. For pipelines PHMSA assigns levels of seriousness based on cost, consequence, injuries and fatalities.  Significant incidents include any of the following: (1) Fatality or injury requiring in-patient hospitalization, (2) $50,000 or more in total costs,(3) release of significant volumes of gas or hazardous liquid. Serious incidents include a fatality or injury requiring in-patient hospitalization.  In civil aviation each serious incident is investigated by the NTSB, an impartial group of experts who determine technical cause but do not assign blame. The available evidence from the U.S. civil aviation industry, pipeline industry, and many national statistical agencies suggest incident reporting should be mandated to ensure statistically reliable data.  This entails significant penalties for not reporting incidents. Ex. Pipeline and Hazardous Materials Safety Administration (PHMSA), Heathrow International Airport, Japan Construction Industry Association

2. 3D mapping of underground infrastructure prior to planning and design. Making the location of underground infrastructure available to engineers so that designers have access to not only accurate above-ground survey but also accurate below-ground location information enables engineers to avoid underground infrastructure during design. 3D maps of underground utilities also contributes to reducing unnecessary and costly utility relocation. Below-ground location information should be at least ASCE quality level B.  The entire area should be should be assessed by an SUE engineer in collaboration with utilities and telecoms with equipment in the area. The assessment may include scanning with modern remote-detection tools (EMI, GPR and inertial locating ) to raise the quality of location of all underground facilities to QL B and to identify abandoned or unknown infrastructure.  The cost of raising the quality level of facilities in the design area to B could be assigned to the relevant network operator, engineering firm or shared. For unknown and abandoned equipment an attempt should be made to find the original owner. Ex. Colorado 811

3. Locating unknown and abandoned facilities.  The current one-call system is targeted toward utilities locating their own facilities, typically based on their as-builts.  But there is no formal mechanism for locating facilities that have been abandoned or are not shown on network operator as-builts.  Requiring a full SUE survey in addition to a traditional surface survey at part of planning and design at the beginning of a construction project helps avoid surprises during construction. Ex. Colorado 811
   

4. Capturing and sharing the location of infrastructure detected as a result of a SUE survey at the beginning of a project or as the result of an information request to one-call/811.  Currently utilities are required to paint the ground and in some jurisdictions to provide a paper sketch indicating the location of underground utilities.   This information needs to be captured digitally and shared.  The objective is over time to build up a high quality (QL A and B) database of the location of underground infrastructure that can be shared.  Ex. Colorado Department of Transportation

5. Capturing and sharing the location of infrastructure exposed during construction. In the United States it is estimated that $10 billion is spent annually to locate underground infrastructure prior to and during construction.  Much of this information is not shared and the next time excavation occurs in the same area, the underground infrastructure must be located again.  If this information is captured and shared, over time a high quality (QL A and B) database of the location of underground infrastructure will be formed that will avoid locating the same infrastructure over and over again.  Alternatives for recording the location of exposed infrastructure include total station, RTK, and LiDAR, which tend to be expensive but high quality (QL A). Other alternatives are consumer photography with control points or structures with accurately known locations.  It is essential that this does not increase excavation costs for the contractor.  Contractor margins are tight and having to keep a survey crew on hand during excavation would significantly increase costs. There have been experiments by the City of Chicago, Bentley and Costain aimed at efficiently capturing location information about utilities exposed during construction.

6. An efficient process to update the information recorded in network operators' databases. Information captured as part of a SUE survey, as a result of an information request to one-call/811, or detected during excavation may differ from the records contained in network operators' databases.  For continuous improvement of the quality of the information about the location of network facilities requires an efficient way to compare and update this information.

7. Reducing or eliminating the update backlog.  Utilities regularly maintain underground infrastructure, move it as part of a construction project, or abandon it.  This information has to be reported back to the network operator to update the information in the utility GIS.  There are two dimensions to updates; the accuracy of the location information provided from the field and the update backlog, the time it takes for updates to be entered in the utility GIS.  As with the as-built backlog this backlog can stretch into months.  The objective should be better than a day. This issue can also be resolved by regulation or by a suitable liability model. Ex. Ofgem in the U.K. requires backlogs to not exceed 42 calendar days.

8. Improving the accuracy of location information for new underground infrastructure.  If all new facilities are located to survey quality, over time location accuracy will continue to improve  as older facilities are retired. Alternatives for recording the location of newly installed infrastructure include total station, RTK, LiDAR, and photogrammetry with control points or structures with accurately known locations.  Whatever the technology the result should be ASCE quality level A.  Special provision must be made for capturing the location of facilities installed using horizontal (trenchless) drilling, for example, inertial mapping of pipe networks.  Since reliable as-builts are generally a network operator responsibility - policies are required to ensure that as-builts for newly installed equipment are accurate. There are several ways to do this; legislation which enables a government or regulator to conduct QA/QC checks on submitted as-builts or a shared liability model that assigns some responsibility for subsurface utility damage to network operators whose as-builts are inaccurate or out-of-date. A  liability model would assign liability of any underground damage during subsequent excavation to the network operator if the as-built location information is incorrect. Ex. City of Calgary, Singapore

9. Reducing or eliminating the as-built backlog.  If the time it takes for as-built information to enter the utility GIS or other database from the time new infrastructure is installed is measured in months or longer, the utility GIS is not sufficently reliable for locating underground infrastructure for construction purposes.  The objective should be better than a day. This can be resolved by regulation or by a suitable liability model.  Ex. Ofgem in the U.K. requires as-built backlogs to be less than 42 calendar days.

10. Assigning a quality level based on a generally accepted quality standard to every piece of underground infrastructure. This is critical for determining the type of excavation equipment that it is appropriate to use. It can also provide the basis for a shared liability model.  Ex. ASCE 38-02 in the U.S., CSA S250 in Canada, PAS 128 in the U.K., France DICT

11. Digitalizing the capture and sharing of information about the underground.  In North America, most one-call legislation only requires marking the ground prior to the initiation of construction.  In Ontario a written record is required in addition to marking the ground. At the federal level in Canada there is legislation initiated in the Senate and that offers the alternative of the exchange of only a written record of the location of utilities mapped prior to excavation - no visit to the site to mark the ground is required. This would open the door to exchanging a digital record of the location of utilities found prior to excavation which would be much more efficient because it could obviate the need to visit the site of the proposed excavation.  However, it would also a higher quality standard for the location of underground infrastructure than is currently the practice.  Ex. ROADIC (Japan), KLIP in Flanders, KLIC in the Netherlands

12. Digitalizing the flow of information about underground infrastructure requires a generally recognized standard for sharing information about the subsurface. The Open Geospatial Consortium (OGC) is developing an underground information exchange standard, with the appropriate acronym MUDDI, that is intended to provide an open standards-based way to share information about the below ground. There are a number of data models for different types of underground infrastructure and geotechnics. MUDDI builds on and augments existing standards to create a unified model supporting multiple use cases. The MUDDI model is intended to support routine street excavations, emergency response, utility maintenance programs, large scale construction projects, disaster planning and response, and smart cities programs. For street excavations the requirement is location of all entities with high horizontal, medium vertical accuracy (2.5D) of underground infrastructure; for large construction projects, detailed 3D geometry of underground infrastructure and detailed 3D geotechnics; for emergency response, interdependencies between different networks; for utility maintenance, network topology and facility location and condition; and for smart cities the ability to monitor and relate streams of data from sensors. This has not yet been adopted by a jurisdiction, but agencies in the U.K. (Ordnance Surevy), Singapore (Singapore Land Authority), and New York (Fund for the City of New York) are actively supporting the development of the standard.

13. Efficient information flow.  Requiring vans with locating crews from several network operators to visit the site of a proposed excavation just prior to construction to scan the ground for their facilities using EMI and GPR and mark the ground is inefficient. An on-line system that allows an engineer or contractor to go online and define a polygon enclosing the proposed excavation and then within less than a day providing access to maps of underground infrastructure in the area can save network operators time and money.  However, the effectiveness of this solution is highly dependent on the quality of the location information maintained by network operators.  In North America the current one-call system requires that underground facilities be mapped to ASCE QL B before starting construction.  An online system providing digital maps composed of utility operators' as-builts would lower the accuracy of the location information provided to contractors and in the absence of other measures would likely increase underground utility damage. Ex, KLIP in Flanders, KLIC in the Netherlands.

14. Rules for the appropriate type of excavation equipment.  Rules are required that restrict the type of excavation equipment based on the quality level of underground utilities identified by network operators.  For example if facilities have been assigned ASCE quality level C or D, only hydraulic, vacuum or hand excavation may be used.  Ex. Heathrow airport

15. Security, privacy and protecting competitive information. To enable this information to be useful in reducing the risk of underground infrastructure damage during construction it has to be shared in a secure way which respects privacy.  In particular it must protect competitive information. There are a number of organizational ways of doing this; government can mandate, implement and run the system, government can mandate but leave it to the private sector to implement and run, an industry consortium with or without government mandate can implement and run the system, regulations could require sharing this information but leave it to the private sector to implement and run, or a private company could take overall responsibility.  Around the world there are examples where each of these alternatives can be found.  The information should be available to engineers during the planning and design phases of construction projects, to contractors for use during excavation, and to organizations responsible for operating and maintaining highways and other civil structures.  Other potential use cases for this data include disaster planning and emergency response.  Ex. KLIP in Flanders and KLIC in the Netherlands, North East Underground Infrastructure Hub (NEUIH) in Newcastle, England

16. Liability model for sharing responsibility for costs of underground utility damage.  The advantage of a rule-based shared liability model that assigns varying levels of responsibility to both contractors and network operators is that it provides motivation to network operators to improve the quality of their location information about their underground infrastructure existing and new.  An example of a shared model is the following: if a network operator identifies the location of a piece of underground equipment as Quality Level A according to the ASCE 38-2 standard and an excavator hits it, the excavator would be liable for costs if the facility was where the network operator said it was, or the network operator would be liable if it wasn't.  For an excavator intending to dig in an area where there is underground infrastructure assigned to level C or D, the cost to bring all infrastructure to quality level B would lie with the network operator (as it does now with North American one-call systems). If the network operator declines to do this, the liability for any underground damage would lie with the network operator. Ex. France DICT

These measures not only can reduce the risk of underground utility damage and the associated risk to the public during construction and thereby lower insurance costs, but can also significantly reduce the cost of infrastructure construction, for example, by avoiding major utilities and reducing the unnecessary and costly moving of utilities on civil engineering projects.

Experience has shown that over time these elements can result in increasingly accurate digital representations showing the location of underground infrastructure that is available to stakeholders in construction projects including planners, engineers, contractors and facilities managers, for utility maintenance, and potentially for other use cases such as utility outage management, disaster planning, emergency response and smart city programs.

Singapore's standard for location of underground utilities

Straits Times

In August 2017 the Singapore Land Authority (SLA) released a standard and specifications for the procedure and practice of utility surveying in Singapore.  The standard specifies the data that should be captured for new underground utilities including telecommunication, sewerage, water supply, electric power, gas, and drainage. It specifies that after installing utilities and prior to filling the trenches an as-built survey should be performed by a registered surveyor to capture the location of the utilities with horizontal accuracy of ±100mm and vertical accuracy of ±100mm. It specifies that the survey equipment to be used should be a total station, GNSS Real Time Kinematic (RTK), or 3D Laser Scanning.

This standard is not mandated by the Singapore Government but is intended to provide a baseline to be incorporated in construction contracts. Since 85% of land is owned by the Singapore government, if a major government agency such as the Urban Redevelopment Authority (URA) routinely incorporated this standard in its contracts as part of standard procurement practice, it would effectively become a de facto mandate. 

In addition to location, the standard also defines the attribute information to be captured.  For example, for an electric power cable, the standard specifies that x,y,z should be surveyed at 20 meter intervals for a straight line cable and more frequently for a curving cable.  In addition, height, width, number of columns, number of rows, number of ducts, number of cables and quality level should also be captured. The quality standard used in Singapore is; 1) ±100mm, 2) ±300mm, 3) ±500mm, 4) Unknown accuracy and 5) Trenchless method.  In Singapore most underground utility work is open trench, although there is some trenchless which requires gyro surveying.

The standard does not specify format or what is to be done with the as-built information.  Currently in Singapore there is nothing in place to require sharing of information about the underground like Netherland's BRO or the British National Underground Asset Registry (NUAR) project.  But there is a Digital Underground project underway to create an ecosystem for a digital twin of the underground as part of the Mapping Singapore in 3D project.  The digital underground project was initiated by the Singapore Land Authority with the the support of the Urban Redevelopment Authority.  The standard for underground utility surveying would create a basic data model for sharing information about underground utilities.

British standard PAS128 for underground utility location to be updated

Belgium underground gas line explosion during excavation 2003

As we are reminded by the recent underground utility hits in San Francisco, CA, Durham, NC, and Calgary, Alberta, not knowing the location underground utilities represents a serious risk for the public. There are 400,000 hits per year in the U.S. alone.  Standards for reporting the reliability of the locational information about underground utilities have been in place for decades but these standards do not reflect recent advances in underground utility detection technology. In the U.S. the 2003 ASCE 38-02  ,which is been used for classifying the quality of location information about underground infrastructure, is widely seen as being out of date. In France the 2012 presidential decree defines three explicit levels of cartographic accuracy for underground structures: A - less than 40 centimeters, B - 40 centimeters to 1.5 meters, and C - greater than 1.5 meters. In Canada the CSA S250 (2011) standard also specifies absolute precision with three different quality levels for exposed utilities and one for remote sensed detection. In the UK the 2014 Publicly Available Specification (PAS) 128, developed under the auspices of the British Standards Institution (BSI) and sponsored by the Institution of Civil Engineers (ICE) and others, not only includes the A,B, C, D quality levels of the U.S. standard, but extends it with explicit precision levels B1 to B4 similar in this respect to the French decree and the Canadian S250 standard.  I have just had a chance to chat with Andy Rhoades who was responsible for locating and mapping underground infrastructure at Heathrow airport for many years and is now leading the process to update PAS128.  Andy told me that this process will kickoff in a couple of weeks with a target of completion roughly six weeks after that.

Just as a reminder PAS128 defines quality levels A through D based on the type of survey used to locate underground utilities.

QLD - Desktop search techniques were used to identify existing utility data by identifying known utility owners within the survey area, requesting asset information from each of them, typically as-builts, and compiling the collected information.  Locational accuracy generally poorly known.

QLC - Requires site reconnaissance to identify above-ground visible physical features that are indicative of and help locate utilities within the survey area. Locational accuracy undefined.

QLB - For this quality level PAS requires that at least two remote sensing techniques must be used in detecting utilities.  Electro-magnetic locating (EML) and ground penetrating radar (GPR) are required, but others may be used in addition. Most EML systems only detect metal, do not have the capability of digitally recording what was detected, and can only provide rough estimates of depth.  GPR is able to provide 3D location, is not able by itself to identify the type of utility, and does not work well in certain types of soils such as clay.  Post-processing is often used with GPR to improve the interpretation of GPR data by resolving weak and intermittent signals or distinguishing multiple targets.

In addition PAS128 breaks the QLB level into several sublevels with specified absolute precision depending on the results of remote sensing.

QLB4 -  A utility cable or pipe is believed to exist but has not been detected. Locational accuracy undefined.
QLB3 - Only the horizontal location of the utility has been detected by one of the geophysical techniques used. Locational accuracy ±500 mm (XY),  Z locational accuracy undefined.
QLB2 - Horizontal and vertical location of the utility was detected by one of the geophysical techniques used. Locational accuracy for X,Y ±250 mm or ±40% of detected depth whichever is greater, for Z ±40% of detected depth.
QLB1 - Horizontal and vertical location of the utility was detected by multiple geophysical techniques. Locational accuracy for X,Y ±150 mm or ±15% of detected depth whichever is greater, for Z ±15% of detected depth.

QLA - Involves exposing the target utilities within the survey area by excavation to confirm and record the location and other attribute data.  Locational accuracy for X,Y ±50 mm, for Z ±25 mm.

In contrast with the standards in other countries PAS128 reflects the advances in underground detection technology - hardware and software - that have occurred in the last few years.  That it is now being updated suggests that PAS128 will continue to stay with the underground detection technology curve.

Urgent: Standards-based geospatial + BIM interoperability requires broad vendor participation

At the International Standards Summit 2019 in Düsseldorf a group of people representing owners, engineering and construction firms, vendors and services providers in the AEC space, and standards organization Open Geospatial Consortium (OGC) and buildingSMART International (bSI) were invited to meet to discuss ways to move forward in promoting a standards-based approach to geospatial + BIM interoperability.

The BIM and geospatial interoperability challenge is the latest symptom of the broader problem of integrating AEC and geospatial workflows, that has contributed to low productivity in the construction sector.  One of the areas of broad agreement at the meetup was that developing a standards-based approach to the BIM+geospatial interoperability problem is urgent.  There are two reasons for this.

The first is that there is growing evidence of the significant business benefits of an integrated BIM+geospatial full lifecycle approach to construction. Design-build-finance-maintain (DBFM), build-operate-transfer (BOT), and public-private-partnerships (PPP) are among the projects that have reported positive benefits of an integrated approach.

The second reason for urgency is that without standards proprietary interoperability will become the de facto standard. In November 2017 the BIM and geospatial market-leaders Autodesk and ESRI announced an agreement to address the interoperability problem. Since then both ESRI and Auto desk have been busy implementing proprietary ways to bring each other's data into their software environment.

ArcGIS is ESRI's market-leading GIS product.  Revit is Autodesk's market-leading BIM application that is utilized by designers for vertical BIM (buildings), although there are landscape architects that have managed to use it as well. Revit models include spatial data and related non-spatial information.  With the release of ArcGIS Pro 2.2 in June 2018 direct reading of Revit BIM (.RVT) files is now supported. In the past Revit models had to be imported through conversion to IFC (Industry Foundation Classes) files and then go through a second conversion to an ESRI geodatabase.  ArcGIS Pro 2.2 makes it possible to open a Revit BIM model directly. Tools are provided for correctly georeferencing BIM models in ArcGIS. Revit data added to ArcGIS behaves like any other 3D GIS data and can be queried, measured and analyzed.

InfraWorks is Autodesk's application that allows civil engineers to design roads and highways in context. InfraWorks 19.2, released in September 2018, now supports the Autodesk Connector for ArcGIS. Designers and engineers can bring GIS content from ArcGIS Online into InfraWorks allowing content such as roads, pipelines, and electrical transformers to be directly imported. The link is dynamic making it possible to build an InfraWorks model directly from GIS data published into ArcGIS Online. When the GIS data is updated, the InfraWorks model can be updated and refreshed. With the release of Autodesk Civil 3D 2019 InfraWorks models can be brought into Civil 3D, Autodesk's civil design product. Together these enhancements enable workflows from ArcGIS through InfraWorks to Civil 3D.

Together these implementations represent a proprietary (but incomplete) solution to the BIM+geospatial interoperability challenge.  If you happen to use Tekla, Bentley BIM, Vectorworks or Graphisoft as your BIM software or QGIS, GeoServer/MapServer/PostGIS, GeoMedia, MapInfo, Manifold, or Smallworld as your GIS software, this does not begin to solve your problem.  The objective of the OGC/buildingSMART partnership is to provide a standards-bases solution to the interoperability problem. The Integrated Digital Built Environment Subcommittee (IDBE SC) was founded to increase interoperability between the geospatial and built environment domains, specifically through coordination of standards development activities of the OGC and buildingSMART International (bSI).

At the meetup in Düsseldorf IDBE was represented by Hans-Christoph Gruler of Leica Geosystems, Leif Granholm of Trimble and Jim Plume of bSI Australasia. Also present were representatives of Bentley Systems, NavVis, Solibri(Nemetschek), Schiphol Airport, Hong Kong Housing Authority, Royal Haikoning, CRB, think project!, and others.  Together these folks represent owners, the construction sector, and vendors. 

A second conclusion of the meetup is that the IDBE SC needs more involvement from all sectors of the construction industry, but especially broader representation from vendors and owners. To date most of the efforts that I am aware of involve attempting to map the OGC standard CityGML to bSI's IFC standard.  It is fair to say that the research to date has shown that this is not possible in general.  Leif Granholm has championed another approach to the problem that moves interoperability up the stack from data models to the software level.  To be successful this requires participation from the major vendors in the geospatial  and BIM spaces. Owners, especially government, can encourage a standards-based as opposed to a proprietary approach to interoperability by mandating or requiring standards in RFIs, RFPs and contracts.

Canadian standard specifies absolute precision for underground infrastructure exposed by excavation

Infrastructure in the older cities of Canada was installed more than 100 years ago when as-built drawings, if any existed, referenced surface features that may have disappeared.  Recording the accurate location of such utilities was not formally required. Today, many of the records that do exist are in formats that are incompatible between utilities and may represent schematics rather than geospatially accurate maps of underground utilities. Inaccurate location of underground infrastructure has implications for public safety and disaster management and represents a significant drag on the economy. A number of national standards have been developed including in the U.S. (ASCE 38-02), U.K (PAS 128)., France and Australia. 

In Canada the purpose of the Canadian Standards Association CSA S250 Standard from 2011 is to specify the mapping records requirements used to identify and locate underground utility infrastructure. This Standard is intended to promote the use and drive the advancement of mapping records during the planning, design, construction, and operation of underground utility infrastructure.  Impetus for the widespread adoption of S250 could be provided by a Senate Bill S-229 that is currently before the House of Commons that opens the door to a digital system (similar to the Dutch KLIC and Belgian KLIP) that does not require an operator to actually visit planned excavation sites by providing digital maps instead.

The standard defines levels of accuracy for recording the location of underground infrastructure when the infrastructure has been exposed either by potholing or during excavation.

• Record accuracy level 0 — There is no information available related to spatial accuracy. The position as shown on the drawings is the best possible estimate of the actual location.
• Record accuracy level 1 — For exposed infrastructure.  Horizontal and vertical location of underground utilities shall be measured while exposed and recorded in a real world coordinate system by a competent individual. Accuracy ± 25 mm in the x, y, and z coordinates.
• Record accuracy level 2 — For exposed infrastructure. Horizontal and vertical location of underground utilities shall be measured while exposed and recorded by a competent individual. Accuracy ± 100 mm in the x, y, and z coordinates,
• Record accuracy level 3 — Horizontal and vertical location of underground utilities shall be measured while exposed and recorded by a competent individual. Accuracy ± 300 mm in the x, y, and z coordinates.
• Record accuracy level 4 — For exposed infrastructure. Horizontal and vertical location of underground utilities shall be measured while exposed and recorded by a competent individual. The measurements shall be tied into either a relative feature or geodetic datum. Accuracy ± 1000 in the x, y, and z coordinates.
• Record accuracy level 5 — For infrastructure that has not been exposed.  Location measured and recorded by a competent individual using geophysical methods. These less precise measurements shall be tied to either a relative feature or geodetic datum. Accuracy ± 1000 mm in the x and y coordinates.  Accuracy of the z coordinate if measures is not quantified.

Furthermore the standard states that if the criteria for accuracy level 0 to 5 are not used, the owner is referred to other standards, specifications, or instructions from the utility.  The A, B, C, D quality levels of the American Society of Civil Engineers (ASCE) 38 standard for underground infrastructure is explicitly referenced for this purpose.  A rough mapping between these two standards appears to be as follows

• Record accuracy level 0 - Quality level D
• Record accuracy level 1 - Quality level A
• Record accuracy level 2 - Quality level A
• Record accuracy level 3 - Quality level A
• Record accuracy level 4 - Quality level C
• Record accuracy level 5 - Quality level B

The Canadian standard is similar to the Australian standard in specifying different levels of absolute accuracy for exposed utilities.  This represents a substantive difference between the Canadian and Australian standards and ASCE 38-02. 

The S250 standard has adopted the widespread but dated practice that the only way to accurately determine the location of underground infrastructure is by exposing and measuring location.  The S250 standard references geophysical methods including electromagnetic methods, ground penetrating radar, and sonding methods requiring insertion of a source of a magnetic field (the sonde) into a pipe or conduit and detecting it at the surface, but the S250 standard clearly doesn't reflect confidence in locations determined by these technologies. 

IDS Stream multi-channel GPR utilized by T2 Utility Engineers

Recent advances in ground penetrating radar and other remote sensing technologies and the high cost of potholing, estimated at $30,000 per pothole, suggest that standards for the reliability of the location of underground infrastructure should include estimated precision for remotely sensed infrastructure.  The U.K. PAS 128 standard, which was adopted in 2014, does this.  The ASCE 38-02 and the PAS 128 standards are being updated, possibly to reflect the development of improved underground remote sensing hardware and software.

Thanks to Mark Braiter and Laverne Hanley for providing access to the S250 standard.

Modeling multi-utility interdependent underground networks for disaster management in cities

On this blog most of the discussion relating to underground infrastructure has been focused on construction focussing on the risks to workers and the public and the drag on the economics of construction.  There are other important impacts to not knowing where underground utilities and telecommunications infrastructure are.  During natural and man-made emergencies, there are two problems relating to underground infrastructure that emergency managers have to face.  The first is that, as Scott Sternfeld emphasized at the December Open Geospatial Consortium (OGC) Energy Summit at EPRI in Charlotte, there is no public regional, state or national outage map in the U.S.  Emergency management personnel have to go to each utility one by one. Utilities may not have an online outage map, which means calling them.  This problem is exacerbated by a lack of shared, reliable information about the location of infrastructure.  Together these problems severely hamper first responders.  At the Energy Summit Tatjana Kutzner, working with Thomas Kolbe, presented on a utility extension to the OGC standard for city modeling, CityGML, that allows modeling of multi-utility networks in an urban environment including interdependencies between them.

Disaster management use case

Thomas Becker; Claus Nagel and Thomas H. Kolbe

I remember being impressed by the UK Environment Agency's flood modeling simulations after the 2007 floods in the UK.  And also by Ergon Energy's flood assessment during the Queensland floods in 2011.  In both these examples a digital terrain model and information about building footprints and elevations were used to determine if a substation or a pumping station were likely affected.  It seemed to me at the time that using that information plus network connectivity from utilities would make it possible to determine customers who likely were without power or water.  From a utility GIS perspective this is not a difficult calculation.  Many utilities know for about 85% of their customers which feeder they are attached to and a simple network trace would enable them to determine who will likely be affected by a transformer or substation outage.  Thomas Kolbe and co-workers having been working for some time on a standards-based model for interdependent utility networks to provide a foundation for this type of modeling.

Thomas Becker; Claus Nagel and Thomas H. Kolbe

The next step is determining interdependencies.  If a feeder providing power to a pumping station has lost power, then using the water utility's network connectivity it is possible to determine which customers are likely without water.  If all interdependencies are considered including electric power, communications, water, district heating, and others it is possible to determine all the customers who are affected by a storm or other disaster, how they are affected and to prioritize restoration efforts.

Integrated modeling of multi-utility networks

Standards exist for modeling specific types of utility networks, for example, for electric power the CIM and Multispeak standards are widely used.  However, there is currently no standard for representing all utilities in an urban environment including interdependencies. At the Energy Summit Tatjana Kutzner presented on the work that she and others are doing to address this serious lack of sharable information for emergency managers.

To provide emergency managers access to the utility information they need to put together a composite assessment of the impact of a storm, flood or other disaster requires a model that can model network 3D geometry (location), topology and function, can represent all utility networks simultaneously, can represent the interdependencies between them, is hierachical - able to represent high, medium and low voltage electric or transmission and distribution water networks, and is able to interact with a city model to ultimately determine who is affected by a disaster and how.  Such a model makes enables analysis and visualization during a disaster and to simulate different different disaster scenarios.

Utility application domain extension (ADE)

Thomas Kolbe and co-workers are the developers of the CityGML standard that has been adopted by the Open Geospatial Consortium.  There are several Application Domain Extensions (ADEs) that have been developed to extend CityGML to other domains.  In 2010 a basic extension Utility Networks ADE was proposed for city utility networks.  The intention is to model infrastructure networks both as a 3D topographic, topological and and functional network. In other words, this is not simply a compilation of network as-builts, but includes the function of each component and its relationships to other components.  It knows the difference between different network topologies; water, electric power, steam, wastewater, and communications.  It also knows the interdependencies between different networks.

Tatjana explained how the Utility Network ADE extends CityGML to utilities with a common network core, different network components including functional components and materials classes and packages for specific utilities: electricity, district heating, water and so on.  She also discussed how the Utility ADE relates to existing network  standards.  For example, the electric network package is based on CIM and allows interoperability with CIM.  It doesn't include all of CIM, but only those elements that are important for the use cases that the Utility ADE is intended to address.

Underground utilities in Berlin SIMKAS 3D

Applications

She described a several projects that have used the utility ADE to model different disaster scenarios.

• Simulating cascading failures in Berlin (SIMCAS 3D)
• Risk analysis of supply infrastructure for the German Armed Forces.  Simulation of the propagation of an explosion at a substation to determine how many people would be affected in order to estimate the number of water trucks that would be required to provide water.
• Linking below ground and above ground infrastructure (Xander den Dujin Masters Thesis TU Delft).  Simulation of damage to the below ground electric power network and using pgRoute to determine which street lights would be out.
• Modelling, simulation and visualization of dependencies between drinking water and electrical networks at a combined drinking water facility hydroelectric power station in Nanaimo, British Columbia (Isaac Boates Masters Thesis University of Applied Sciences Karlsruhe).

I should add parenthetically that although there is no public regional, state or national outage map in the U.S.  there are ways of mapping outages using social networks.  DataCapable's Global Power Outage Tracker mines social media and then generates map visualizations using a GIS.  The data is presented on a mapping dashboard, showing the time and location of each tweet found.

Conclusion

The Utility Network ADE Core extension supports geospatial, topographic and functional modeling of multi-utility networks.  It supports modeling of different types of networks including electric power, water, and gas networks.  Because it is an extension to the CityGML urban model the ADE supports linking utility networks with city structures including residential, commercial and industrial.  It is designed to build on existing utility network models such as CIM for electric power networks. It provides a data model for modeling multi-utility scenarios including interdependencies and can be applied for analyzing, visualizing and simulating the disaster scenarios mentioned at the beginning of this blog which involve cascading network failures.  In addition it probably contains all of the data elements required for including distribution analytics for electric power and water networks which would enable this to provide the basis for dynamic modeling of multi-utility networks.

Progress toward a unified model for underground infrastructure and geology

TNO, Geological Survey of the Netherlands

Information about the location, condition and interdependencies of the infrastructure and geology below our feet is poor or lacking.  Even though information about what is below ground is revealed by every excavation, it is rarely shared.  At the December Open Geospatial Consortium (OGC) Energy Summit at EPRI in Charlotte, Josh Lieberman of the OGC presented an overview of the progress of OGC's underground information initiative, with the appropriate acronym MUDDI, which is intended to provide an open standards-based way to share information about the below ground.

Unreliable information about what is underground including infrastructure and supporting structures and their interdependencies; soil, sediment, fill, and interstitial water and air; and physical, biological, and chemical properties leads to risk of injury to workers and the public and produces a significant drag on the construction sector.   Josh quoted an estimate from the the Institution of Civil Engineers (ICE) that about 50% of cost and time over-runs on civil engineering projects are caused by 'unforeseen ground conditions. If we are going to optimize where and how we build, we need much better information about what is below ground at the planning stage. To give a practical example close to home, in the middle of the Ottawa LRT project, a huge sink hole which unexpectedly appeared in the middle of a major street in Ottawa was blamed for a significant delay in the project as well as serious traffic disruptions.

There are a number of data models for different types of underground infrastructure and geology which raises the question; why do we need another ? The answer is twofold; in the context of a smart city we need to be able visualize and analyze all this information together, not just one network at a time.  Secondly MUDDI is not an attempt to replace existing standards, but to build on and augment existing standards to create a unified model supporting multiple perspectives.

Use cases

The MUDDI project has identified several different broad use cases that the model is intended to support including routine street excavations (EX), emergency response (ER), utility maintenance programs (OM), large scale construction projects (AE), disaster planning and response (DP), and smart cities programs (SC). For each of these, several basic requirements that the model needs to satisfy have been identified.  For street excavations the requirement is location of all entities with high horizontal, medium vertical accuracy (2.5D) of underground infrastructure; for large construction projects, detailed 3D geometry of underground infrastructure and detailed 3D geology;  for emergency response, interdependencies between different networks; for utility maintenance, network topology and facility location and condition; and for smart cities the ability to monitor and relate streams of data from sensors.

To provide a way for the model to be used by different types of users, the concept of profiles has been introduced. Profiles have been used for other OGC standards and allow for different levels of complexity for different domains and applications. The proposed profiles include asset, excavation, emergency, planning and integration profiles.

Reference standards

The MUDDI model is intended to build on and be compatible with many existing reference/target models.  For infrastructure these include CityGML with Utility Network ADE (Application Domain Extension) , INSPIRE Utility Networks, IMKL (Information model for cable and pipes), BIM-IFC, Land and Infrastructure Conceptual Model (LandInfra), Singapore Underground Geospatial Model, PipelineML, Underground Pipeline Information Management System, CIM (Common Information Model), Multispeak, ESRI Utility Model, and GEOfeature.  For geology, the reference/target models are GeoSciML, INSPIRE Geology, GroundwaterML, BGS National Geological Model, EarthResourceML, GeoTOP, SoilEML, IFC Geotechnical Extension, MINnD, and BoreholeIE.

Next steps

Josh outlined the next steps in the development of the MUDDI model which include implementations, experimental and prototype deployments with real world data, and estimates of returns on investment (ROI).

ESRI and Autodesk partnership for BIM and geospatial interoperability: one year later

The BIM and geospatial interoperability challenge is the latest symptom of the broader problem of integrating AEC and geospatial workflows, that has contributed to low productivity in the construction sector. After the announcement about a year ago by Jack Dangermond and Andrew Anagnost of a new relationship to build a bridge between Autodesk and ESRI technologies, I thought it a good time to review progress toward interoperability between the AEC and geospatial worlds.

ESRI and Autodesk partnership

In the mid-1990s Autodesk and ESRI, market leaders in their respective areas of CAD and GIS, attempted to collaborate to address the CAD and GIS interoperability problem. The result of the agreement between Jack Dangermond and Carol Bartz at the time resulted in an unsuccessful product called ArcCAD, which satisfied neither CAD nor GIS users.

A year ago Autodesk and ESRI, again agreed to collaborate. Expected benefits cited by Autodesk and ESRI from BIM and GIS interoperability include "unprecedented reductions in permitting through improved stakeholder engagement, more sustainable and resilient design through enhanced project insight, reduced risk via improved end-to-end flow of materials, resource availability and scheduling during construction," and "providing industry and city planners the ability to design in the context of the real world enabling communities to build connected, resilient, sustainable cities and infrastructure." This time around they are probably more aware of the technical and cultural issues hindering AEC and geospatial interoperability.

Integrating BIM and CAD with GIS

Revit is Autodesk's market-leading BIM application that is utilized by designers for vertical BIM (buildings), although there are landscape architects that have managed to use it as well. Revit models include spatial data and related non-spatial information.  With the release of ArcGIS Pro 2.2 in June 2018 direct reading of Revit BIM (.RVT) files is now supported. In the past Revit models had to be imported through conversion to IFC (Industry Foundation Classes) files and then go through a second conversion to a geodatabase.  ArcGIS Pro 2.2 makes it possible to open a Revit BIM model directly. Tools are provided for correctly georeferencing BIM models in ArcGIS. Revit data added to ArcGIS behaves like any other 3D GIS data and can be queried, measured and analyzed.

ESRI has provided for some time a product for AutoCAD users who want to work with ArcGIS data in a familiar context. It allows CAD users to edit GIS data, navigate drawings using location, imtegrate with GIS, and turn CAD data into GIS data. Shortly after the partnership announcement, an incremental release of ArcGIS for AutoCAD 370 was announced with support for the latest versions of AutoCAD. ESRI product management also promised that the future of ArcGIS for AutoCAD would continue with improved integration with ArcGIS Online/Portal. ArcGIS Pro 2.2 provides updated support for reading and exporting AutoCAD version 2018 and 2019 format files. Furthermore ESRI product management said that other CAD/BIM/AEC applications were being considered for future development using a similar integration pattern as ArcGIS for AutoCAD.

Integrating GIS with civil workflows

InfraWorks is Autodesk's application that allows civil engineers to perform conceptual design for roads and highways in context. InfraWorks 19.2, released in September 2018, now supports the Autodesk Connector for ArcGIS. Designers and engineers can bring GIS content from ArcGIS Online into InfraWorks allowing content such as roads, pipelines, and electrical transformers to be directly imported. The link is dynamic making it possible to build an InfraWorks model directly from GIS data published into ArcGIS Online. When the GIS data is updated, the InfraWorks model can be updated and refreshed. With the release of Autodesk Civil 3D 2019 InfraWorks models can be brought into Civil 3D, Autodesk's civil design product. Together these enhancements enable workflows from ArcGIS through InfraWorks to Civil 3D.

Integrating civil and geospatial workflows with BIM

A major challenge is interoperability between Autodesk's own products. A first step for integrating geospatial workflows into Revit is for site preparation. Autodesk offers a Site Designer for Revit plug-in that is intended to enable architects, designers, and planners to shape the terrain for building sites using grading tools to model pads, parking lots, streets, sidewalks, and retaining walls. But the integration between Autodesk's BIM and civil engineering products still inhibits site preparation workflows. Civil 3D was developed on the AutoCAD platform. Revit, which was acquired from Charles River Software in 2002, was built on different data structures. As a recent post from a landscape architecture site pointed out there remains a "gaping hole ... between Civil 3D and Revit".

Improving interoperability between the two products has now become a priority for Autodesk product management. According to the latest Autodesk roadmap associated with the Revit 2019 release, Autodesk is investing in improving how civil engineers and architects can collaborate better on the site design process. The very good news is that according to the Revit product management roadmap, collaboration with Civil 3D and Revit is now an "Accepted Revit Idea", which confirms that Revit/Civil 3D interoperability has become a development priority. Furthermore new features in Civil 3D 2019 includes enhanced structural and civil design collaboration for Civil 3D with Revit..

In conclusion the new relationship between Autodesk and ESRI is being translated into concrete actions to improve the interoperability between the AEC and geospatial worlds.  There is a considerable distance to go yet, but there are grounds for optimism that there is a commitment to BIM and geospatial interoperability so that in the future workflows that involve both AEC and geospatial data and software will be able to surmount the CAD+GIS barriers that have represented major inefficiencies for the construction, utility and other sectors for decades.

Using publicly available environmental data in a spatial analysis of low birth weight babies

A spatial analysis of possible environmental factors contributing to the increase in the number of underweight babies born in Canada was presented by Charlene Nielsen at GeoAlberta 2018. Termed low birth weight at term (LBWT), this is the second most important cause of infant mortality in Canada and costs the medical systems hundreds of millions of dollars every year. It is also linked to childhood and adult diseases. Charlene's hypothesis was that environmental factors including chemical pollution, the man made environment, and socioeconomic level were contributing factors to low birth weight babies in Canada.  She used spatial analytics to study the problem which she used as the basis for her PhD thesis at the University of Alberta.

Using open, publicly available databases Charlene related the spatial distribution of low birth weight babies to geographical proximity to air-based chemical emissions or to land-based pollutants related to electrical power lines, dumps and solid waste sites, gas stations, mine sites and tailings, oil and gas well pads, transformer stations, and crop lands.

One of the publicly available data sources for chemical emissions that she used is the National Pollutant Release Inventory which has been maintained by Environment and Climate Change Canada since 1993.  It currently monitors the emissions of 324 chemical substances.

Her study found that air-released or land-based pollutants may be more important depending on geographical location. There was a greater correlation of low birth weight babies with the environmental factors she studied in Ontario, Quebec, Alberta and British Columbia. While this study found that  environmental factors did contribute to low birth weight babies, these are not the only factors. This study was particularly interesting because it used the geographical distribution of low weight births and the spatial distribution of environmental factors to try to determine some of the factors contributing to low weight births. Secondly it used publicly available environmental data which demonstrates that this type of spatial analysis can be easily applied in other studies.